C.12. Extension Objects, Enums, and Typedefs

Expanding on previous discussion, extensions can add values to existing
enums; and can add their own commands, enums, typedefs, etc. This is done
by adding to vk.xml. All such additions will
be included in the vulkan.h header supplied by Khronos.

Note

Application developers are encouraged to be careful when using switch
statements with Vulkan API enums. This is because extensions can add new
values to existing enums. The use of a default: statement, within a
switch, may avoid future compilation issues.